Google Analytics is simple, elegant, valuable, free and tells you a lot about your website traffic.
Google Analytics is easy to install. All you need to do is paste a few lines of HTML, which Google provides to you, into any webpage for which you want to monitor traffic.
It's simple, elegant, valuable and free.
The few lines of code, when executed by the browser when a person visits your webpage, send a signal to the Google Analytics server to say "hey dude, I'm looking at this page!". Google Analytics then stores all this data from all the visits to the page, and uses it to construct different graphs (like how many visitors, where they originated, etc.). It's just like you might create a chart in Excel with a table of data. No rocket science there.
Strangers can't view your Google Analytics charts because they can't log in to your Google Analytics account, and they can't insert their own Google Analytics HTML into your web page because they can't log into that either.
Google Analytics is a great way to find out which keywords are working and which are not.
Google Analytics shows you such things as how many unique visitors you get every day, what % of them visit only one page then go away (called the "bounce rate"), what search words visitors used to get there if they did a search, and a bunch of other stuff. It's a great way to check how effective your new search words are.
Search for "Google Analytics" and sign up for the service. It will walk you through the steps of getting the HTML you need to add to your web pages. It will also tell you where exactly to add them.
Your web person (or perhaps you are that person) will update the web pages on the server. If you are using a Content Management System (CMS), you might only have to add the HTML to the master template, and the system will wash it down to every page. That all depends on how your CMS system works.
Good luck!